High and low volume horn



Feb. 23, 1954 c. A. BEST ET AL 2,670,467 HIGH AND LOW VOLUME HORN Filed NOV. 14, 1950 I N VENTORS CLEAFE A- BEST w LLOYD E JOHNSON BY q V AMW ATTORNEY Patented Feb. 23, 1954 HIGH AND LOW VOLUME HORN Oleafe A. Best, Jackson, and Lloyd E. Johnson, Parma, Mich., assignors to Sparks-Withington Company, Jackson, Mich., a corporation of Application November 14, 1950, Serial No. 195,679

3 Claims. 1

The present invention relates to improvements in magnetic type horns for automotive vehicles in which provisions are made for sounding a warning signal of either relatively low volume for city driving or greater volume for country driving. This type of horn is constructed with a field, an armature, a field coil, a pair of contact breaker points, means for breaking the points, and preferably means for reducing the arc across the point where the points break interrupting the flow of current in the field coil.

In horns of the aforesaid type, the flow of current in the field coil sets up a magnetic flux in the iron of the field. When the breaker points are opened and current ceases to flow through the field coil, the field collapses and a voltage is induced in the coil. Due to the rapidity of the collapse of the field, the induced voltage becomes so high that an arc is created, across the points, of such intensity that the point life is very short unless means is provided to reduce the rapid collapse of the field.

It is the accepted practice to reduce the rapid collapse of the field by a resistor which is shunted across the points. When the points open, the resistor is in series with the current source and the field coil. Therefore, a certain amount of current is passed through the field coil even though the points are separated and this small amount of current retards the collapse of the field and reduces the voltage across the points whereby satisfactory point life is obtained. This resistor which protects the points must be of a value that will not pass enough current to retard the movement of the horn diaphragm and thus reduce the maximum sound output of the horn, but will pass just enough current to keep the voltage down across the points. It is this type of magnetic horn to which the principles of the present invention have been applied.

In the patented art, a great many horns for accomplishing the results or" the present invention have been proposed. Perhaps the patent to White, No. 2,283,659, granted May 19, 1942, is the most pertinent disclosure with respect to our development.

The aforesaid White patent has a resistor for controlling the output of the horn in parallel with the field coil and in the form of a shunt. According to the present invention, the resistor controlling the output of the horn is in series with the field coil. With our arrangement all the current, at all times, passes the field coil in lieu of a portion of the current being carried through a shunted branch in which White pro- 2 vides his resistor for controlling the operation of the horn.

Thus an object of the invention is to provide an improved horn of the type described in which the output is controlled by a resistor in series with the field coil, the resistor being connected between the coil and the breaker points and in parallel with the point protection resistor when one is used.

Another object is to provide a horn of the type described in which all of the current flows into the field coil during both high and low volume output of the horn.

These and other objects and advantages residing in the combination, construction and arrangement of parts will more fully appear from a consideration of the following specification and the appended claims.

In the drawing is shown a wiring diagram of the horn embodying the principles of the present invention.

Referring to the drawing, the current source takes the form of a battery It] having a ground connection l2 and a connection l4 extending to the usual horn switch it. The field coil 58, breaker points 20, and connection 232 to ground are of conventional design and arrangement as is the point protection resistor 2A.

To accomplish the low and high volume output of the horn, the output resistor 26 is connected in series with the coil is with a switch 28 connecting the resistor 26 to ground. With this arrangement, with the switch 28 in either of its selected open or closed positions, all of the current from the source It! will flow through the field coil Hi. In practice, the resistor 26 may have a resistance in the order of 0.5 ohm as compared with the resistance of the point protection resistor 24 which may be in the order of 2.0 ohms. It is to be understood that these resistance values maybe changed from that disclosed and are merely given here for the purpose of citing an example of an arrangement found to be practical.

The resistor 26 by being in parallel with the resistor 24 will pass enough current, with the switch 28 closed, when the points 20 are open, to keep the field fiux high enough in the coil it to reduce the movement of the diaphragm of the horn to a point where the sound output is at a desired city driving level.

With our improved horn circuit, there is no voltage change during the power stroke of the armature when maximum power is required to said control resistor active or inactive to regulate the flow of current through said field coil when said points are open whereby the travel of the diaphragm is selectively reduced to reduce the sound output of the horn, and a selectively actuated switch in series with said source and field coil; thrcughwhich the entirei current fiows to actuatezthe horns 2. In a magnetic type horn, the combination flux in the field high enough to a t; as a brak nwith a field coil for actuating the armature operon the diaphragm assembly, slowing up its movement and reducing its travel, thereby reducing" the amount of air moved, by the diaphr.agn1,.

which cuts down the sound voutput-;of:the horn.

ating the diaphragm of the horn, a pair of contact breaker points adapted to be operated by said armature, activated. by said field coil, a point protection'resistou in series with said field coil In the wiring diagram showngthexarrangementc and;shuntinggsaidrpoints, an output volume con- 26 and ground, the volume control resistor is,

made active or inactive depending on the position oftheswitch 28.

Inthediagrammatic showing, the diaphragm 300i the, horn has an armature 32 with anactuator;3.4fonthe shaftfit and movingwith the armature. 32, engaging) with the. one, of, the arms, carrying the points to open the same, allin a.

well knownmanner.v

We claim: 7 1'. A magnetic type. horn circuit for selective high and low volume soundoutput comprising a currentsource,,a fieldcoillfor, actuating an armature. cperatingthe diaphragmvof the horn,- a.

pair. cfJcontact breaker points actuated by the armature,.an outputvolumeicontrol resistor in series with said source and field coil ,when the points are open, saidcontrol resistor having a resistance of.- sufiicient value to, maintain-suificientfiux in. the field to reduce the normal travel, of: said.

diaphra m. manual switchv means forv rendering trol resistor in series with said field coil and parallel with. said protection resistor, and switch mechanism for selectively rendering said volume controliresistor active and inactive.

3. In a magnetic typezhorn having a field coil for, operating the armatureattached to thediaphragm offthe horn,,a;pair. of contactbreaker: points actuated by' the armature and apoint pro-- tection resistor in series with said field coil, an, output-volume control-resistor connectedin series, with said fieldvcoil and parallel tosaid protection; resistor, and selectively operableswitch mecha-- nism for, renderingsaid volume control resistor; active, and inactive to. regulatethe flow oflcurr" rent, through the .field .coil when; said pointsare:

open.

CLEAFE f A. BEST; LLQYD.- E. J .OHNSONH References Cited in thefile" of this patent UNITED STATES,- PATENT-S:

Number Name; Date.

1;0l6;699: Manson: Feb. 6, 1912 1,172,713 Hutohison Feb. 22, 1916' 2,203,420 Scofield et.: a1; June 4, 1940" 2,283,659. White .May19, 1942 2,340,502 Baker- '.Feb; 1,, 19442 

